Abstract: 〗［Abstract］ Objective〖HTSS〗〓 To study the efficacy of debridement combined with 420 nm intense pulsed light in the treatment of the moderate to severe acne and the depressed scar and inflammatory erythema.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓Two hundred and fiftyfour cases of acne patients were  divided into two groups. One hundred and twentyeight cases as the treatment group were treated with acne debridement and 420 nm intense pulsed light, 126 cases as the control group were treated with 420 nm intense pulsed light. 1 times every 2 weeks, a total of 4 times. After 2 months in the end of treatment，the curative effect, occurrence of depressed scar and regression of inflammatory erythema were evaluated.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓The differences in clinical efficacy were statistically significant（P＜001）. The satisfaction of depressed scar was 92.2% in treatment group and 69.8% in control group, there was a significant difference between the two groups(P＜001). As for the extinction time of inflammatory erythema, the treatment group was also significantly faster than the control group(P＜001).
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓Debridement combined with 420 nm intense pulsed light in treatment of moderate to severe acne is more effective than 420 nm intense pulsed light alone. The occurrence of epression scar was significantly reduced, while the inflammatory erythema was promoted.

Key words: acne vulgaris, debridement, cicatrix